/*
 * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch_helpers.h>
#include <assert.h>
#include <css_pm.h>
#include <debug.h>
#include <plat_arm.h>
#include "../scpi/css_scpi.h"
#include "css_scp.h"

/*
 * This file implements the SCP power management functions using SCPI protocol.
 */

/*
 * Helper function to inform power down state to SCP.
 */
void css_scp_suspend(const psci_power_state_t *target_state)
{
    uint32_t cluster_state = scpi_power_on;
    uint32_t system_state = scpi_power_on;

    /* Check if power down at system power domain level is requested */
    if (CSS_SYSTEM_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
        system_state = scpi_power_retention;

    /* Cluster is to be turned off, so disable coherency */
    if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
        cluster_state = scpi_power_off;

    /*
     * Ask the SCP to power down the appropriate components depending upon
     * their state.
     */
    scpi_set_css_power_state(read_mpidr_el1(),
                 scpi_power_off,
                 cluster_state,
                 system_state);
}

/*
 * Helper function to turn off a CPU power domain and its parent power domains
 * if applicable. Since SCPI doesn't differentiate between OFF and suspend, we
 * call the suspend helper here.
 */
void css_scp_off(const psci_power_state_t *target_state)
{
    css_scp_suspend(target_state);
}

/*
 * Helper function to turn ON a CPU power domain and its parent power domains
 * if applicable.
 */
void css_scp_on(u_register_t mpidr)
{
    /*
     * SCP takes care of powering up parent power domains so we
     * only need to care about level 0
     */
    scpi_set_css_power_state(mpidr, scpi_power_on, scpi_power_on,
                 scpi_power_on);
}

/*
 * Helper function to get the power state of a power domain node as reported
 * by the SCP.
 */
int css_scp_get_power_state(u_register_t mpidr, unsigned int power_level)
{
    int rc, element;
    unsigned int cpu_state, cluster_state;

    /*
     * The format of 'power_level' is implementation-defined, but 0 must
     * mean a CPU. We also allow 1 to denote the cluster
     */
    if (power_level != ARM_PWR_LVL0 && power_level != ARM_PWR_LVL1)
        return PSCI_E_INVALID_PARAMS;

    /* Query SCP */
    rc = scpi_get_css_power_state(mpidr, &cpu_state, &cluster_state);
    if (rc != 0)
        return PSCI_E_INVALID_PARAMS;

    /* Map power states of CPU and cluster to expected PSCI return codes */
    if (power_level == ARM_PWR_LVL0) {
        /*
         * The CPU state returned by SCP is an 8-bit bit mask
         * corresponding to each CPU in the cluster
         */
#if ARM_PLAT_MT
        /*
         * The current SCPI driver only caters for single-threaded
         * platforms. Hence we ignore the thread ID (which is always 0)
         * for such platforms.
         */
        element = (mpidr >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
#else
        element = mpidr & MPIDR_AFFLVL_MASK;
#endif  /* ARM_PLAT_MT */
        return CSS_CPU_PWR_STATE(cpu_state, element) ==
            CSS_CPU_PWR_STATE_ON ? HW_ON : HW_OFF;
    } else {
        assert(cluster_state == CSS_CLUSTER_PWR_STATE_ON ||
                cluster_state == CSS_CLUSTER_PWR_STATE_OFF);
        return cluster_state == CSS_CLUSTER_PWR_STATE_ON ? HW_ON :
            HW_OFF;
    }
}

/*
 * Helper function to shutdown the system via SCPI.
 */
void __dead2 css_scp_sys_shutdown(void)
{
    uint32_t response;

    /*
     * Disable GIC CPU interface to prevent pending interrupt
     * from waking up the AP from WFI.
     */
    plat_arm_gic_cpuif_disable();

    /* Send the power down request to the SCP */
    response = scpi_sys_power_state(scpi_system_shutdown);

    if (response != SCP_OK) {
        ERROR("CSS System Off: SCP error %u.\n", response);
        panic();
    }
    wfi();
    ERROR("CSS System Off: operation not handled.\n");
    panic();
}

/*
 * Helper function to reset the system via SCPI.
 */
void __dead2 css_scp_sys_reboot(void)
{
    uint32_t response;

    /*
     * Disable GIC CPU interface to prevent pending interrupt
     * from waking up the AP from WFI.
     */
    plat_arm_gic_cpuif_disable();

    /* Send the system reset request to the SCP */
    response = scpi_sys_power_state(scpi_system_reboot);

    if (response != SCP_OK) {
        ERROR("CSS System Reset: SCP error %u.\n", response);
        panic();
    }
    wfi();
    ERROR("CSS System Reset: operation not handled.\n");
    panic();
}
